Here's the code:

<script >
function Calculate() {
   var Original = document.getElementById("V1").value;
   var New = Original * 1.06;
   document.getElementById("Result").innerHTML = "Result = " + New;
}
</script>

<input id="V1" placeholder="Enter a number here..."/>
<input id="Submit" value="Submit" onclick="Calculate()"/>
<br><br>
<div id="Result"></div>

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I wouldn't actually tweet this page as it's hidden from the site menu

Click the Tweet button to see the popup with the pre-defined text....you can cancel before sending the Tweet